Protective film of polarizing plate

ABSTRACT

A protective film for use with a polarizing plate has a support carrying a glare-proof layer. The glare-proof layer is a resin with coarse particles having an average particle size of 0.25 to 10 μm, and fine particles having an average particle size of 0.1 μm or less and a refractive index of 1.40 to 1.60, embedded in it.

FIELD OF THE INVENTION

The present invention relates to a protective film of a polarizing plateand in particular to a protective film of a polarizing plate exhibitingeffective glare-proof and excellent transmission visibility.

BACKGROUND OF THE INVENTION

Triacetyl cellulose type resins have been used as a protective film of apolarizing plate. Recently, polarizing plates are used for a variety ofapplications under various environments and in response thereto, aprotective film for polarizing plates with further added value in usehas been desired. As one of the added values is cited glare-proofing toprevent glare of the surface of the image plane of liquid crystal. Forexample, there is employed a means for glare-proofing, in which fineparticles such as silica are contained in the outermost surface of theprotective film of the polarizing plate.

SUMMARY OF THE INVENTION

When using a protective film of a polarizing plate, in the outermostsurface thereof, fine particles such as silica to prevent glare of thesurface of the image plane of the liquid crystal, it was proved thatglare-proof effect was exhibited but transmission visibility of thepolarizing plate was markedly reduced due to the presence of the fineparticles. Accordingly, an object of the present invention is to find atechnique of enhancing a glare-proofing function and providing excellenttransmission visibility of the produced polarizing plate.

The object of the present invention is accomplished by

(1) a protective film of a polarizing plate, characterized in that saidprotective film comprises a support having a glare-proof layercomprising coarse particles having an average particle size of 0.25 to10 μm, and fine particles having an average particle size of 0.1 μm orless and a refractive index of 1.40 to 1.60; and

(2) a polarizing plate comprising a polarizing film containing apolarizer and provided thereon a protective film which comprises asupport having thereon a glare-proof layer, wherein said glare-prooflayer comprises coarse particles having an average particle size of 0.25to 10 μm, and fine particles having an average particle size of 0.1 μmor less and a refractive index of 1.40 to 1.60.

BRIEF DESCRIPTION OF THE DRAWING

The drawing shows a polarizing plate carrying a glare-proof layer inaccordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawing, a polarizing film 20 is shown carrying aglare-proof layer 10 with both coarse particles 12 and fine particles14. The glare-proof layer 10 is carried on support 16 which in turn iscarried on the polarizing film with an adhesion facilitating layer 18disposed therebetween.

The coarse particles 12 having an average size of 0.25 to 10 μm arethose which are allowed to be present in the vicinity of the outermostsurface of the protective film 10 of the polarizing plate 20, andthereby glare-proof of the surface of the picture area of liquid crystalbeing achieved. The average particle size thereof is within the range of0.25 to 10 μm.

The coarse particles 12 include inorganic particles and organicparticles. Examples of the inorganic particles used in the inventioninclude silicon oxide, titanium oxide, aluminium oxide, zinc oxide, tinoxide, calcium carbonate, barium sulfate, talc, kaolin, and calciumsulfate. As to the organic particles, poly(metha)acrylate type resin,silicone type resin, polystyrene type resin, polycarbonate type resin,acrylstyrene type resin, benzoguanamine type resin, melamine type resin,polyolefin type resin, polyester type resin, polyamide type resin,polyimide type resin, and polyfluoroethylene type resin are usable.

Among these, silicon oxide such as silica is particularly preferred toeffectively achieve the glare-proof aimed in the invention. Amongsynthetic amorphous silica of the silicon oxide is preferredfine-powdered, water containing silicate prepared through a wet process.The thus prepared silicate was proved to be markedly effective inlowering luster. The wet process is a method in which sodium silicate isallowed to react with a mineral acid and salt in an aqueous medium. Thecoarse particles which are commercially available include, for example,Silicia produced by Fuji Silicia Co., ltd. and Nipsil E produced byNihon Silica Co., ltd.

The average particle size of the coarse particles 12 was determined asfollows. At first, a cross-sectioned photomicrograph of a samplecontaining the particles was taken and the diameter was measured withrespect to 1,000 particles taken in the photograph, by using an imageprocessing device, LUZEX-III produced by NIRECO Co., ltd. to obtain anaverage value thereof.

The fine particles 14 having an average particle size of 0.1 μm or lessand an refractive index of 1.40 to 1.60 are allowed to be present in thevicinity of the outermost surface of the protective layer of thepolarizing plate, whereby glare-proof by the coarse particles 12 iseffected, and further providing superior transmission visibility to theprotective film of the polarizing plate.

The fine particles 14 include inorganic particles and organic particles.Examples of the inorganic particles usable in the invention includesilicon oxide, titanium oxide, aluminum oxide, zinc oxide, tin oxide,calcium carbonate, barium sulfate, talc, kaolin, and calcium sulfate. Asto the organic particles, poly(metha)acrylate type resin, silicone typeresin, polystyrene type resin, polycarbonate type resin, acrylstyrenetype resin, benzoguanamine type resin, melamine type resin, polyolefintype resin, polyester type resin, polyamide type resin, polyimide typeresin, and polyfluoroethylene type resin are usable.

Among these, silicon oxide such as silica is particularly preferred toachieve the glare-proof and transmission visibility aimed in theinvention. As the fine silicon oxide particles is preferred silicaprepared through a dry process and in particular, anhydrous silicateprepared by a combustion method is preferred. The thus prepared silicatewas proved to be markedly effective in enhancement of transmissionvisibility. The dry process is a process in which fine-powdered,anhydrous silicate particles are formed at a high temperature of 1,000°C. or higher. In the process, vaporized silicon tetrachloride is mixedwith hydrogen and the mixture is subjected to combustion at 1,000 to1,200° C. under open air to obtain super fine particles. Commerciallyavailable particles, for example, f include Aerosil produced by NihonAerosil Co., ltd. The afore-described wet process and the above dryprocess are both referred to e.g., "Filler Katsuyo-Jiten" (PracticalHandbook of Filler) pages 65-66, published by Taisei-sha.

Examples of the fine particles 14 having an refractive index of 1.40 to1.60 include polymethyl methaacrylate fine particles having a refractiveindex of 1.50; silica fine particles having a refractive index of 1.46;polyacryl fine particles having a refractive index of 1.49; polystyrenefine particles having a refractive index of 1.50; polyvinyl chloridefine particles 14 having a refractive index of 1.54; polycarbonate fineparticles 14 having a refractive index of 1.58; alumina fine particles14 having a refractive index of 1.56, etc.

The average size of the fine particles 14 was determined in thefollowing manner. At first, a sample of the invention containing thefine particles 14 was enveloped with epoxy resin, extremelythinly-sliced section was prepared by a microtome, and cross-sectionedtransmission electronmicrograph (TEM) thereof was taken. The diameterwas measured with respect to 1,000 particles taken in the photograph toobtain an average value thereof.

The glare-proof layer 10 according to the invention plays a role ofpreventing light of such as fluorescent lamp from being reflected in theimage plane to improve clearness of liquid crystal display provided witha polarizing plate, and containing material capable of irregularlyreflecting the light.

The polarizing plate according to the invention comprises a polarizingfilm 20 containing a polarizer and laminated thereto a protective film.In addition thereto, a phase plate may be included. The protective filmis laminated to the polarizing film 20 with an adhesive. As theadhesive, polyvinyl alcohol type adhesives such as polyvinyl alcohol andpolyvinyl butyral, and vinyl type latexes such as butyl alcohol areusable. The polarizing film 20 which is a main constituting element ofthe polarizing plate is an element capable of allowing light having awavefront polarized in a direction to pass through. A representativepolarizing film 20 is a polyvinyl alcohol type polarizing film 20,including polyvinyl alcohol type film dyed with iodine or a dichroicdye. One which is prepared by uniaxial-stretching and dying or viceversa and preferably subjecting to durability treatment with a boroncompound is preferred.

A preferred embodiment of the present invention is a protective film ofa polarizing plate having a glare-proof layer comprising coarseparticles 12 having an average particle size of 0.25 to 10 μm andhydrophilic fine particles 14 having an average particle size of 0.1 μmor less and a refractive index of 1.40 to 1.60. The hydrophilic fineparticles 14 described above are referred to as fine particles 14 havinghydrophilic surface. Alternatively, the hydrophilic fine particles arereferred to as those having high, adsorbed moisture content andconcretely, having 0.5% or more of a moisture content at 80% R.H. and25° C.

According to the invention, such hydrophilic fine particles arepreferably used, and those having the moisture content of 1.5% or moreare more preferred in terms of superiority in transmission visibility.The moisture content can generally be measured by using a Karl-Fischertype moisture meter. According to the invention, the moisture content ofthe fine particles 14 was measured by using a micro-moisture meter,CA-06 and moisture-vaporizing apparatus, VA-06 (both produced byMitsubishi Chemical Corp.

In cases where fine polymethyl methaacrylate particles or fine titaniumoxide particles are used as the hydrophilic fine particles,hydrophilicity thereof can be provided with a OH group or by treatingtheir surface with a metal oxide such as Al₂ O₃. As hydrophilic silicaparticles are employed those having a high density of silanol group.

Further, another preferred embodiment of the present invention is aprotective film of a polarizing plate having a glare-proof layer 10 witha thickness of 0.5 to 5.0 μm, and comprising coarse silicon oxideparticles 12 having an average particle size of 1.1 to 2.0 times thelayer thickness and fine silicon oxide particles having an averageparticle size of 0.005 to 0.1 μm; and thereby, the protective film of apolarizing plate exhibiting sufficient glare-proof effect and superiortransmission visibility can be obtained, and by the use thereof, thepolarizing plate superior in preventing occurrence of sparkle can beprovided. The coarse silicon oxide particles 12 are particles comprisedof silicon oxide such as silica, playing a role of preventing glare ofthe surface of liquid crystal imaging plane. The fine silicon oxideparticles 14 are fine particles 14 comprised of silicon oxide such assilica, which are present together with the coarse silicon oxideparticles, preventing glare of the surface of liquid crystal imagingplane and providing a polarizing plate exhibiting superior transmissionvisibility.

The average particle size of the fine silicon oxide particles is definedsimilarly to the case of the fine particles having an average particlesize of 0.1 μm or less, as afore-described. The fine silicon oxideparticles 14 are preferably hydrophilic ones in terms of superiority intransmission visibility. The hydrophilic fine silicon oxide particles 14are those having a high density of a silanol group on the surface and ahigh moisture-absorption content, i.e.,the moisture-absorption contentat 80% R.H. of 0.5% or more and preferably, 1.5% or more. The averageparticle size thereof is preferably 0.008 to 0.015 μm.

The glare-proof layer 10 with a thickness of 0.5 to 5.0 μm, asabove-described is a layer comprising coarse silicon oxide particles andfine silicon oxide particles, and having function to prevent glare ofthe surface of liquid crystal imaging plane.

The glare-proof layer 10 may be any one which comprises coarse siliconoxide particles 12 and fine silicon oxide particles 14 dispersed in abinder such as diacetyl cellulose, and having a desired thickness. It ispreferred to use an actinic ray-hardenable resin as a binder. A layercontaining the actinic ray-hardenable resin is cured by exposing toactinic ray after coating to form a hardened resin layer containingcoarse silicon oxide particles and fine silicon oxide particles. Thus, aglare-proofing clear hard layer obtained by the use of the actinicray-hardenable resin is preferred in terms of capability of providingfurther additional functions to one layer and enhancing mechanicalstrength of the surface of the polarizing plate.

The actinic ray-hardenable resin used in the invention is a resincapable of being hardened upon exposure to ultraviolet ray or electronbeam through cross-linking reaction. As representative examples of theactinic ray-hardenable resin are cited an ultraviolet ray-hardenableresin and electron beam-hardenable resin, and a resin capable of beinghardened upon exposure to an actinic ray other than ultraviolet ray andelectron beam may be usable. Examples of the ultraviolet ray-hardenableresin include ultraviolet ray-hardenable polyester-acrylate type resins,ultraviolet ray-hardenable acrylurethane type resins, ultravioletray-hardenable acrylate type resins, ultraviolet ray-hardenablemethaacrylate type resins, ultraviolet ray-hardenable polyester-acrylatetype resins and ultraviolet ray-hardenable polyol-acrylate type resins.

Ultraviolet ray-hardenable polyol-acrylate type resins usable in theinvention are photopolymerizable monomers/oligomer, such astrimethylolpropane-triacrylate, di-trimethylolpropane-tetraacrylate,pentaerythritol-triacrylate, pentaerythritol-tetraacrylate,di-pentaerythritol-pentaacrylate, di-pentaerythritol-hexaacrylate andalkyl-modified di-pentaerythritol-pentaacrylate. These polyol-acrylatetype resins are highly curable and markedly hardenable, characterized inthat they are little in hardening shrinkage, low in odor and toxicityand high in safety.

The ultraviolet ray-hardenable polyol-acrylate type resin may usable incombination with another type ultraviolet ray-hardenable resin, such asultraviolet ray-hardenable epoxy type resin. Hardened coating layer ofacrylate type resin is large in curling due to its hardening shrinkageand interfere with handling. Epoxy type resins are small in hardeningshrinkage and curling of the hardened coating layer. The ultravioletray-hardenable epoxy type resin is comprised of a compound containing atleast two epoxy groups in the molecule, containing a cationicpolymerization initiator and being capable of curing reaction uponexposure to ultraviolet ray.

Electron beam-hardenable resins usable in the invention are preferablythose having an acrylate type functional group, such as a relatively lowpolymeric polyester resin, polyether resin, acryl resin, epoxy resin,urethane resin, alkyd resin, spiroacetal resin, polybutadiene resin andpolythiol-polyene resin.

To achieve markedly and easily effects of the invention, the ultravioletray-hardenable resin is preferably used.

The actinic ray-hardenable resin relating to the invention is hardenedon exposure to electron beams or ultraviolet rays. In the case ofelectron beam hardening, there can be employed electron beam emittedfrom various types of electron beam accelerators such asCockcroft-Walton type, van de Graaff type, resonance transformer type,insulated core transformer type, linear type, dynamitron type and highfrequency type and having an energy of 50 to 1,000 KeV, preferably 100to 300 KeV. In the case of ultraviolet ray hardening, there can beemployed ultraviolet rays emitted from lamps such as ultra-high pressureUV lamp, high pressure UV lamp, low pressure UV lamp, carbon arc, xenonarc, metal halide lamp.

According to the invention, the layer thickness can be measure byobserving the section of the protective film, based on itselectronmicrograph. Thus, observed values with respect to ten differentportions are averaged out to obtain the layer thickness. The thicknessof the glare-proof layer 10 relating to the invention is preferably 0.5to 5.0 μm and more preferably, 2.0 to 4.0 μm.

As to the average particle size of coarse silicon oxide particles, theexpression, "an average particle size of 1.1 to 2.0 times the layerthickness" means that, in case of the layer thickness of 0.5 μm, forexample, the average particle size of silicon particles is within therange of 0.55 to 1.0 μm; and in case of the layer thickness of 5.0 μm,the average particle size is 5.5 to 10.0 μm.

The glare-proof layer 10 according to the invention is provided on atransparent resin film 16. The transparent resin film may be any onewhich can be used as a protective film of a polarizing plate. Examplesthereof include a cellulose acetate film, polyester film, polycarbonatefilm, norbornen type resin film, polyacrylate film and polysulfon resinfilm. Among these are preferred cellulose acetate film such as cellulosetriacetate and polycarbonate type resin film in terms of durability andmechanical strength.

The cellulose acetate resin film usable in the invention may be any oneknown in the art. Combined acetic acid of the cellulose acetate (i.e.,weight percentage of acetic acid bonded to the cellulose) is preferably50 to 62% and more preferably 56 to 62%. The weight-average molecularweight of the cellulose acetate is preferably 70,000 to 120,000 and morepreferably, 80,000 to 100,000.

The cellulose triacetate may partially be esterified with an fatty acidother than acetic acid, such as propionic acid and butylic acid, as faras the combined acetic acid amount is satisfied as above-described. Asfar as the combined acetic acid is satisfied in total amount, celluloseesters such as cellulose propionate or cellulose butyrate may becontained.

The cellulose triacetate film used in a protective film of a polarizingplate generally contains a plasticizer. Examples thereof includephosphates such as triphenyl phosphate and tricresyl phosphate andphthalates such as diethyl phthalate and dimethyl phthalate.

As polycarbonate resin usable in the invention, aromatic carbonates arepreferred in terms of their chemical and physical properties, and inparticular, bisphenol A type polycarbonate is preferred. Among them,bisphenol A type derivatives, in which a benzene ring, cyclohexane ringor aliphatic hydrocarbon group is introduced in the phenol A moiety, aremore preferable. In particular is preferred a polycarbonate obtained bymaking use of the derivative in which at least one of these group isintroduced asymmetrically with respect to the central carbon atom. Forexample, a polycarbonate obtained by making use of a carbonate such thattwo methyl groups attached to the central carbon atom of bisphenol A arereplaced by phenyl group or a hydrogen atom of each benzene ring ofbisphenol A is replaced by a substituent such as methyl or phenyl group,asymmetrically with respect to the central carbon atom is preferablyused. Concretely are those obtained, through a phosgene method ortransesterification method, from 4,4'-dihydroxy-diphenylalkane or itshalogen substituted derivative, such as 4,4'-dihydroxy-diphenylmethane,4,4'-dihydroxy-diphenylethane or 4,4,'-dihydroxy-diphenylbutane.

The polycarbonate resin may be used in the form of a mixture with othertransparent resin such as polystyrene type resin, methyl methaacrylatetype resin or cellulose acetate type resin. At least one side of acellulose acetate type film may be laminated with the polycarbonateresin. A method of preparing the polycarbonate type resin film usable inthe invention is not specifically limited. Films prepared by any of theextrusion method, solvent-casting method and calendering method may beused. Either of a uniaxially stretched film and biaxially stretched filmmay be used. The solvent-casting film is preferred in view ofsuperiority in surface fineness and optical isotropy.

The polycarbonate resin film used in the invention has a glasstransition point of 110° C. or higher (preferably, 120° C. or higher)and water absorption of 0.3% or less (preferably, 0.2% or less), whereinthe water content was measured after being dipped in water at 23° C. for24 hrs.

The protective film of the polarizing plate may be subjected to surfacetreatments, such as adhesion-facilitating treatment, anti-blockingtreatment, anti-curling treatment, clear-hardening treatment,anti-reflection treatment and antistatic treatment. Exemplarily arecited embodiments such that (i) a glare-proof layer (e.g., clear-hardtreated layer containing particles and fine particles relating to theinvention) is provided on one side of the transparent resin film(b-side) and the other side (a-side) is subjected toadhesion-facilitating treatment (i.e., treatment for enhancement ofadhesion of the transparent resin film to a polarizing membrane); (ii)the b-side of the transparent resin film is subjected to antistatictreatment and further thereon, a glare-proof layer is provided, and thea-side is subjected to the adhesion-facilitating treatment; (iii) aglare-proof layer is provided on the b-side of the transparent resinfilm and the a-side is subjected to anticurling treatment.

The adhesion-facilitating treatment is to provide function forfacilitating adhesion of the protective film of the polarizing plate toan adjacent layer such as a polarizing membrane. Theadhesion-facilitating treatment can be conducted by surface-activatingtreatment such as a corona discharge treatment, flame treatment, UVtreatment, high frequency treatment, glow discharge treatment, activeplasma treatment, laser treatment and ozone oxidation treatment; or byproviding an adhesion-facilitating layer 18. Among these treatments, itis preferred to provide the adhesion-facilitating layer 18.

As an embodiment of the adhesion-facilitating layer 18, a layercontaining a polymer compound having --COOM group (M represents ahydrogen atom or a cation). Preferably, the layer containing the polymercompound having --COOM group is provided on the side of the protectivefilm, and adjoining thereto and on the side of a polarizing membrane isprovided a layer mainly containing a hydrophilic polymer compound. Inthis case, examples of the polymer compound containing --COOM groupinclude a COOM group-containing styrene-maleic acid copolymer and COOMgroup-containing vinyl acetate-maleic acid copolymer. Particularly, COOMgroup-containing vinyl acetate-maleic acid copolymer is preferred interms of the object of the present invention. The polymer compound maybe used singly or in combination thereof. A weight-averaged molecularweight thereof is preferably 500 to 500,000. Examples of the polymercompound containing --COOM group are shown as below, but the presentinvention is not limited thereto.

Exemplified Compound ##STR1##

Examples of the hydrophilic polymer compound include hydrophiliccellulose derivatives (e.g., methyl cellulose, carboxymethyl cellulose,hydroxycellulose, etc.); polyvinyl alcohol derivatives (e.g., polyvinylalcohol, vinyl acetate-vinyl alcohol copolymer, polyvinyl acetal,polyvinyl formal, polyvinyl benzal, etc.); natural polymer compound(e.g., gelatin, casein, arabic gum, etc.); hydrophilic polyesterderivatives (e.g., partially sulfonated polyethylene terephthalate);polyvinyl derivatives (e.g., poly-N-vinyl pyrrolidone, polyacrylamide,polyvinyl indazole, polyvinyl pyrazole, etc.). These compound may beused singly or in combination thereof.

The antiblocking treatment applicable in the invention is to provideease of handling of a transparent resin film. Thus, it providesfunctions of preventing winding distortion occurred when winding up atransparent resin film and making it easy to recover the windingdistortion.

The anticurling treatment is to provide function of curling so as to beapplied-side-in. Thus, when one side of the transparent resin film issubjected to a surface treatment or both sides thereof are subjected tosurface treatment to different extents or in different manners, theanticurling treatment is to prevent curling in the direction of the sidebeing inside. One embodiment thereof is that the adhesion-facilitatinglayer is coated on one side of the transparent resin film and to theopposite side is applied an anticurling treatment. A concrete method foranticurling includes one by solvent-coating or coating a transparentresin layer. In the method by solvent-coating, there is coated acomposition containing a solvent capable of dissolving or a transparentresin film used as a protective film of a polarizing plate. The solventis used singly or in combination, depending on an extent of curling ofthe transparent resin film and the kind thereof. In addition, aclear-hardening treatment and antistatic treatment also displayedanticurling effects.

The clear-hardening treatment is to achieve clear hardening function, asafore-described as one of binders in glare-proofing treatments. It ispreferably to coat a actinic ray-hardenable resin layer.

The antistatic treatment applicable in the invention is to providefunction of preventing the resin film from charging. One embodimentthereof is to provide a layer containing an ionic conductive material orconductive fine particles. The ionic conductive material is one which iselectrically conductive and contains ions as an electric carrier. Anexample thereof is an ionic polymer compound. The ionic polymer compoundincludes anionic polymer compounds described in examined and publishedJapanese Patents 49-23828, 49-23827 and 47-28937; ionen type polymercontaining a dissociative group in the main chain described in JapanesePatents 55-734, 57-18175, 57-18176, 57-56059, 59-14735 and unexaminedand published Japanese Patent Application (hereinafter denoted as"JP-A") 50-54672; and cationic pendant type polymer containing acationic dissociative group in the side chain described in JapanesePatents 53-13223, 53-45231, 55-145783, 55-65950, 55-67746, 57-15376,57-11342, 57-19735, 58-56858, 61-27853 and JP-A 61-27853 and 62-9346. Anexample of the conductive fine particles is conductive metal oxide. Themetal oxide is preferably ZnO, TiO₂, SnO₂, Al₂ O³, In₂ O₃, SiO₂, MgO,BaO, MoO₂, V₂ O₅ or complex oxide thereof; and ZnO, TiO₂ or SnO₂ isparticularly preferred. As an example containing a hetero atom, additionof Al or In to ZnO, addition of Nb or Ta to TiO₂, and addition of Sb, Nbor halogen element to SnO₂ is effective. The addition amount of thehetero atom is preferably 0.01 to 25 mol %, more preferably, 0.1 to 15mol %. The volume resistivity of these conductive metal oxide powder is10⁷ Ωcm or less, preferably, 10⁵ Ωcm or less. It is preferred that thepowder having a specific structure with a primary particle diameter of100 Å to 0.2 μm and a long-diameter of high-order structure of 300 Å to6 μm is contained in a conductive layer, in amount of 0.01 to 20% byvolume.

EXAMPLES

Embodiments of the invention are exemplarily explained but the inventionis not limited thereto.

Preparation of UV Ray-hardenable Resin Composition A

    ______________________________________                                        Dipentaerythritol hexaacrylate monomer                                                                50 parts (by weight)                                  Dipentaerythritol hexaacrylate dimer                                                                  20 parts                                              Dipentaerythritol hexaacrylate trimer or more                                                         20 parts                                              1,4-butanediol diglycidyl ether                                                                       10 parts                                              Diethoxybenzophenone UV initiator                                                                      2 parts                                              Aromatic sulfonium type UV initiator                                                                 0.5 parts                                              Fluoro-surfactant        1 part                                               Silica (av. primary particle size: 1.8 μm)                                                        2.5 parts                                              Hydrophilic silica (av. particle size: 0.01 μm)                                                     2 parts                                              Methyl ethyl ketone     50 parts                                              Ethyl acetate           50 parts                                              Isopropyl alcohol       50 parts                                              ______________________________________                                    

The above composition was mixed by high-speed stirring machine (TKhomo-mixer produced by Tokushu Kika Kogyo Co., ltd.) and then dispersedusing a collision type disperser (Manton-Gaulin homogenizer produced byGaulin Corp.).

Coating solution of adhesion-facilitating layer (a):

    ______________________________________                                        Lower layer solution                                                          Exemplified compound (1-1)                                                                               0.5 g                                              Acetone                     60 ml                                             Ethyl acetate               30 ml                                             Toluene                     10 ml                                             Upper layer solution                                                          Polyvinyl alcohol (Gosenol NH-26,                                                                        0.5 g                                              produced by Nihon Gosei Kagakukogyo)                                          Saponin (product by Merck)                                                                              0.03 g                                              Water                       50 ml                                             Methanol                    50 ml                                             ______________________________________                                    

Coating solution of adhesion-facilitating layer (b):

    ______________________________________                                        Lower layer solution                                                          Exemplified compound (1-1)                                                                             0.5 g                                                Acetone                   60 ml                                               Ethyl acetate             30 ml                                               Isopropyl alcohol         10 ml                                               Upper layer solution                                                          the same as that of the upper layer                                           solution of (a)                                                               ______________________________________                                    

Preparation of UV Ray-hardenable Resin Composition B

    ______________________________________                                        Dipentaerythritol hexaacrylate monomer                                                                50 parts (by weight)                                  Dipentaerythritol hexaacrylate dimer                                                                  20 parts                                              Dipentaerythritol hexaacrylate trimer or more                                                         20 parts                                              1,4-butanediol diglycidyl ether                                                                       10 parts                                              Diethoxybenzophenone UV initiator                                                                      2 parts                                              Aromatic sulfonium type UV initiator                                                                 0.5 parts                                              Fluoro-surfactant        1 part                                               Silica (av. primary particle size: 4.5 μm)                                                        2.5 parts                                              Hydrophilic silica (av. particle size: 0.01 μm)                                                     2 parts                                              Methyl ethyl ketone     50 parts                                              Ethyl acetate           50 parts                                              Isopropyl alcohol       50 parts                                              ______________________________________                                    

The above composition was mixed by high-speed stirring machine (TKhomo-mixer produced by Tokushu Kika Kogyo Co., ltd.) and then dispersedusing a collision type disperser (Manton-Gaulin homogenizer produced byGaulin Corp.).

Preparation of UV Ray-hardenable Resin Composition C

    ______________________________________                                        Dipentaerythritol hexaacrylate monomer                                                                50 parts (by weight)                                  Dipentaerythritol hexaacrylate dimer                                                                  20 parts                                              Dipentaerythritol hexaacrylate trimer or more                                                         20 parts                                              1,4-butanediol diglycidyl ether                                                                       10 parts                                              Diethoxybenzophenone UV initiator                                                                      2 parts                                              Aromatic sulfonium type UV initiator                                                                 0.5 parts                                              Fluoro-surfactant        1 part                                               Silica (av. primary particle size: 1.8 μm)                                                        2.5 parts                                              Methyl ethyl ketone     50 parts                                              Ethyl acetate           50 parts                                              Isopropyl alcohol       50 parts                                              ______________________________________                                    

The above composition was mixed by high-speed stirring machine (TKhomo-mixer produced by Tokushu Kika Kogyo Co., ltd.) and then dispersedusing a collision type disperser (Manton-Gaulin homogenized produced byGaulin Corp.).

Preparation of UV Ray-hardenable Resin Composition D

    ______________________________________                                        Dipentaerythritol hexaacrylate monomer                                                                50 parts (by weight)                                  Dipentaerythritol hexaacrylate dimer                                                                  20 parts                                              Dipentaerythritol hexaacrylate trimer or more                                                         20 parts                                              1,4-butanediol diglycidyl ether                                                                       10 parts                                              Diethoxybenzophenone UV initiator                                                                      2 parts                                              Aromatic sulfonium type UV initiator                                                                 0.5 parts                                              Fluoro-surfactant        1 part                                               Silica (av. primary particle size: 0.23 μm)                                                         2 parts                                              Hydrophilic silica (av. particle size: 0.01 μm)                                                     2 parts                                              Methyl ethyl ketone     50 parts                                              Ethyl acetate           50 parts                                              Isopropyl alcohol       50 parts                                              ______________________________________                                    

The above composition was mixed by high-speed stirring machine (TKhomo-mixer produced by Tokushu Kika Kogyo Co., ltd.) and then dispersedusing a collision type disperser (Manton-Gaulin homogenized produced byGaulin Corp.).

Preparation of UV Ray-hardenable Resin Composition E

    ______________________________________                                        Dipentaerythritol hexaacrylate monomer                                                                50 parts (by weight)                                  Dipentaerythritol hexaacrylate dimer                                                                  20 parts                                              Dipentaerythritol hexaacrylate trimer or more                                                         20 parts                                              1,4-butanediol diglycidyl ether                                                                       10 parts                                              Diethoxybenzophenone UV initiator                                                                      2 parts                                              Aromatic sulfonium type UV initiator                                                                 0.5 parts                                              Fluoro-surfactant        1 part                                               Silica (av. primary particle size: 0.38 μm)                                                         2 parts                                              Hydrophilic silica (av. particle size: 0.01 μm)                                                     2 parts                                              Methyl ethyl ketone     50 parts                                              Ethyl acetate           50 parts                                              Isopropyl alcohol       50 parts                                              ______________________________________                                    

The above composition was mixed by high-speed stirring machine (TKhomo-mixer produced by Tokushu Kika Kogyo Co., ltd.) and then dispersedusing a collision type disperser (Manton-Gaulin homogenized produced byGaulin Corp.).

Preparation of UV Ray-hardenable Resin Composition F

    ______________________________________                                        Dipentaerythritol hexaacrylate monomer                                                                50 parts (by weight)                                  Dipentaerythritol hexaacrylate dimer                                                                  20 parts                                              Dipentaerythritol hexaacrylate trimer or more                                                         20 parts                                              1,4-butanediol diglycidyl ether                                                                       10 parts                                              Diethoxybenzophenone UV initiator                                                                      2 parts                                              Aromatic sulfonium type UV initiator                                                                 0.5 parts                                              Fluoro-surfactant        1 part                                               Silica (av. primary particle size: 1.0 μm)                                                          2 parts                                              Hydrophilic silica (av. particle size: 0.01 μm)                                                     2 parts                                              Methyl ethyl ketone     50 parts                                              Ethyl acetate           50 parts                                              Isopropyl alcohol       50 parts                                              ______________________________________                                    

The above composition was mixed by high-speed stirring machine (TKhomo-mixer produced by Tokushu Kika Kogyo Co., ltd.) and then dispersedusing a collision type disperser (Manton-Gaulin homogenized produced byGaulin Corp.).

Preparation of UV Ray-hardenable Resin Composition G

    ______________________________________                                        Dipentaerythritol hexaacrylate monomer                                                                50 parts (by weight)                                  Dipentaerythritol hexaacrylate dimer                                                                  20 parts                                              Dipentaerythritol hexaacrylate trimer or more                                                         20 parts                                              1,4-butanediol diglycidyl ether                                                                       10 parts                                              Diethoxybenzophenone UV initiator                                                                      2 parts                                              Aromatic sulfonium type UV initiator                                                                 0.5 parts                                              Fluoro-surfactant        1 part                                               Silica (av. primary particle size: 3.75 μm)                                                         2 parts                                              Hydrophilic silica (av. particle size: 0.01 μm)                                                     2 parts                                              Methyl ethyl ketone     50 parts                                              Ethyl acetate           50 parts                                              Isopropyl alcohol       50 parts                                              ______________________________________                                    

The above composition was mixed by high-speed stirring machine (TKhomo-mixer produced by Tokushu Kika Kogyo Co., ltd.) and then dispersedusing a collision type disperser (Manton-Gaulin homogenized produced byGaulin Corp.).

Preparation of UV Ray-hardenable Resin Composition H

    ______________________________________                                        Dipentaerythritol hexaacrylate monomer                                                                50 parts (by weight)                                  Dipentaerythritol hexaacrylate dimer                                                                  20 parts                                              Dipentaerythritol hexaacrylate trimer or more                                                         20 parts                                              1,4-butanediol diglycidyl ether                                                                       10 parts                                              Diethoxybenzophenone UV initiator                                                                      2 parts                                              Aromatic sulfonium type UV initiator                                                                 0.5 parts                                              Fluoro-surfactant        1 part                                               Silica (av. primary particle size: 4.5 μm)                                                          2 parts                                              Hydrophilic silica (av. particle size: 0.01 μm)                                                     2 parts                                              Methyl ethyl ketone     50 parts                                              Ethyl acetate           50 parts                                              Isopropyl alcohol       50 parts                                              ______________________________________                                    

The above composition was mixed by high-speed stirring machine (TKhomo-mixer produced by Tokushu Kika Kogyo Co., ltd.) and then dispersedusing a collision type disperser (Manton-Gaulin homogenized produced byGaulin Corp.).

Preparation of UV Ray-hardenable Resin Composition I

    ______________________________________                                        Dipentaerythritol hexaacrylate monomer                                                                50 parts (by weight)                                  Dipentaerythritol hexaacrylate dimer                                                                  20 parts                                              Dipentaerythritol hexaacrylate trimer or more                                                         20 parts                                              1,4-butanediol diglycidyl ether                                                                       10 parts                                              Diethoxybenzophenone UV initiator                                                                      2 parts                                              Aromatic sulfonium type UV initiator                                                                 0.5 parts                                              Fluoro-surfactant        1 part                                               Silica (av. primary particle size: 1.88 μm)                                                         2 parts                                              Hydrophilic silica (av. particle size: 0.01 μm)                                                     2 parts                                              Methyl ethyl ketone     50 parts                                              Ethyl acetate           50 parts                                              Isopropyl alcohol       50 parts                                              ______________________________________                                    

The above composition was mixed by high-speed stirring machine (TKhomo-mixer produced by Tokushu Kika Kogyo Co., ltd.) and then dispersedusing a collision type disperser (Manton-Gaulin homogenizer produced byGaulin Corp.).

Example 1

Using above coating solutions prepared, samples were prepared accordingto the following manner.

Preparation of Inventive Sample 1-1

Polycarbonate resin (viscosity-averaged molecular weight of 40,000;bisphenol A type) of 100 parts by weight,2-(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole of 1.0 part byweight, methylene chloride of 430 parts by weight and methanol of 90parts by weight were introduced in a sealed vessel and completelydissolved with stirring at 80° C. under pressure. The resulting solutionwas filtered, then uniformly cast on a stainless band at 33° C. anddried for 5 min. After being dried and peeled off from the stainlessband, drying was completed with transporting with a number of rollers toobtain polycarbonate film with a thickness of 50 μm. In this case, aside in contact with the stainless band is denoted as "b-side" and theopposite side is denoted as "a-side".

On the b-side of the polycarbonate film, UV ray-hardenable resincomposition A was coated so as to have a dry thickness of 3.0 μm anddried at 80° C. for 5 min. Subsequently, the coat was exposed to UVlight emitted from a high pressure UV lamp at a distance of 10 cm apartfor 4 sec. to form UV-hardened resin layer A. Next, on the a-side, thelower layer solution (1) and upper layer solution (2) of theadhesion-facilitating layer (a) were each coated in this order in acoating amount of 20 ml/m² and dried at 100° C. for 5 min. to obtain aninventive sample 1-1.

Preparation of Inventive Sample 1-2

Inventive sample 1-2 was prepared in the same manner as the inventivesample 1-1, except that hydrophilic silica (average particle size of0.01 μm) of 2 parts by weight used in the UV ray-hardenable resincomposition A was replaced by hydrophobic silica (average particle sizeof 0.01 μm) of 2 parts by weight.

Preparation of Inventive Sample 1-3

Inventive sample 1-3 was prepared in the same manner as the inventivesample 1-1, except that hydrophilic silica (average particle size of0.01 μm) of 2 parts by weight used in the UV ray-hardenable resincomposition A was replaced by hydrophilic polymethyl methacrylate(average particle size of 0.01 μm) of 2 parts by weight.

Preparation of Inventive Sample 1-4

Inventive sample 1-4 was prepared in the same manner as the inventivesample 1-1, except that hydrophilic silica (average particle size of0.01 μm) of 2 parts by weight used in the UV ray-hardenable resincomposition A was replaced by hydrophobic polymethyl methacrylate(average particle size of 0.01 μm) of 2 parts by weight.

Preparation of Inventive Sample 1-5

Inventive sample 1-5 was prepared in the same manner as the inventivesample 1-1, except that silica (average particle size of 1.8 μm) of 2.5parts by weight used in the UV ray-hardenable resin composition A wasreplaced by polymethyl methacrylate (average particle size of 3.5 μm) of2.5 parts by weight.

Preparation of Inventive Sample 1-6

Cellulose triacetate (the acetic acid-bonding amount of 61.0%) of 100parts by weight, triphenyl phosphate of 9 parts by weight,2-(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole of 8 part by weight,methylene chloride of 430 parts by weight and methanol of 90 parts byweight were introduced in a sealed vessel and completely dissolved withstirring at 80° C. under pressure. The resulting solution was filtered,then uniformly cast on a stainless band at 33° C. and dried for 5 min.After being dried and peeled off from the stainless band, drying wascompleted with transporting with a number of rollers to obtain cellulosetriacetate film with a thickness of 80 μm. In this case, a side incontact with the stainless band is denoted as "b-side" and the oppositeside is denoted as "a-side".

Inventive sample 1-6 was prepared in the same manner as the inventivesample 1-1, except that the polycarbonate film used in sample 1 wasreplaced by the cellulose triacetate film and a coating solution of theadhesion-facilitating layer (b) was coated on the a-side.

Preparation of Inventive Sample 1-7

Using the polycarbonate film with a thickness of 80 mm used in sample 1,UV ray-hardenable resin composition B was coated on the b-side of thefilm so as to have a dry thickness of 8.0 μm and dried at 80° C. for 5min. Subsequently, the coat was exposed to UV light emitted from a highpressure UV lamp at a distance of 10 cm apart for 4 sec. to formUV-hardened resin layer A. Next, on the a-side, the lower layer solution(1) and upper layer solution (2) of the adhesion-facilitating layer (a)were each coated in this order in a coating amount of 20 ml/m² and driedat 100° C. for 5 min. to obtain an inventive sample 1-7.

Preparation of Comparative Sample 1-1

Comparative sample 1-1 was prepared in the same manner as the inventivesample 1-1, except that hydrophilic silica (average particle size of0.01 μm) of 2 parts by weight used in the UV ray-hardenable resincomposition A was replaced by hydrophilic silica (average particle sizeof 0.25 μm) of 2 parts by weight.

Preparation of Comparative Sample 1-2

Comparative sample 1-2 was prepared in the same manner as the inventivesample 1-1, except that silica (average particle size of 1.8 μm) of 2.5parts by weight used in the UV ray-hardenable resin composition A wasreplaced by polymethyl methacrylate (average particle size of 3.5 μm) of2.5 parts by weight, and hydrophilic silica (average particle size of0.01 mm) of 2 parts by weight was replaced by hydrophilic silica(average particle size of 0.25 μm) of 2 parts by weight.

Preparation of Comparative Sample 1-3

Comparative sample 1-3 was prepared in the same manner as the inventivesample 1, except that hydrophilic silica (average particle size of 0.01μm) of 2 parts by weight used in the UV ray-hardenable resin compositionA was replaced by hydrophilic titanium oxide (average particle size of0.03 μm) of 2 parts by weight.

Preparation of Comparative Sample 1-4

Comparative sample 1-4 was prepared in the same manner as the inventivesample 1-1, except that silica (average particle size of 1.8 μm) of 2.5parts by weight used in the UV ray-hardenable resin composition A wasreplaced by silica (average particle size of 0.2 μm) of 2.5 parts byweight.

Preparation of Comparative Sample 1-5

Using the polycarbonate film with a thickness of 80 mm used in sample 1,UV ray-hardenable resin composition C was coated on the b-side of thefilm so as to have a dry thickness of 3.0 μm and dried at 80° C. for 5min. Subsequently, the coat was exposed to UV light emitted from a highpressure UV lamp at a distance of 10 cm apart for 4 sec. to formUV-hardened resin layer C. Next, on the a-side, the lower layer solution(1) and upper layer solution (2) of the adhesion-facilitating layer (a)were each coated in this order in a coating amount of 20 ml/m² and driedat 100° C. for 5 min. to obtain an comparative sample 1-5.

Thus-prepared inventive samples 1-1 through 1-7 and comparative samples1-1 through 1-5 were each evaluated with respect to their performance,according to the following manner.

Evaluation of glare-proof (measurement of glossiness)

Protective film samples of a polarizing plate were measured with respectto glossiness to evaluate their glare-proofing effect, according to themethod described in JIS K7105 by using a measuring instrument T-2600DAproduced by Tokyo Denshoku Kogyo (60 degree glossiness). Results thereofare shown in Table 1.

Evaluation of Transmission Visibility

Samples were measured with respect to transmission visibility, accordingto the method described in JIS K-7105-1981 by using an imageclarity-measuring machine, ICM-1DO produced by Suga Shikenki. Resultsthereof are shown in Table 1. Transmission visibility (%) was shown as atotal value of four types of optical wedge with widths of 0.125 mm, 0.5mm, 1.0 mm and 2.0 mm.

                                      TABLE 1                                     __________________________________________________________________________               Coarse  Fine                Trans-                                 Layer      particles                                                                             particles           mission                                                                           Film                                     thickness                                                                          Av.size                                                                           mate-                                                                             Av.size                                                                           mate-                                                                            Refractive                                                                             Glossi-                                                                           visi-                                                                             support                            Sample No.                                                                          (μm)                                                                            (μm)                                                                           rial                                                                              (μm)                                                                           rial                                                                             index                                                                              surface                                                                           ness                                                                              bility                                                                            resin                              __________________________________________________________________________    1-1(Inv.)                                                                           3.0  3.5 Silica                                                                            0.01                                                                              Silica                                                                           1.46  a* 62.9                                                                              82.2                                                                              PC                                 1-2(Inv.)                                                                           3.0  3.5 Silica                                                                            0.01                                                                              Silica                                                                           1.46 b   63.1                                                                              70.5                                                                              PC                                 1-3(Inv.)                                                                           3.0  3.5 Silica                                                                            0.01                                                                              TiO.sub.2                                                                        1.50 a   64.2                                                                              62.3                                                                              PC                                 1-4(Inv.)                                                                           3.0  3.5 Silica                                                                            0.01                                                                              TiO.sub.2                                                                        1.50 b   63.5                                                                              60.1                                                                              PC                                 1-5(Inv.)                                                                           3.0  3.5 PMMA                                                                              0.01                                                                              Silica                                                                           1.46 a   48.7                                                                              74.9                                                                              PC                                 1-6(Inv.)                                                                           3.0  3.5 Silica                                                                            0.01                                                                              Silica                                                                           1.46 a   62.8                                                                              82.5                                                                              TAC                                1-7(Inv.)                                                                           8.0  9.0 Silica                                                                            0.01                                                                              Silica                                                                           1.46 a   65.4                                                                              69.1                                                                              PC                                 1-1(Comp.)                                                                          3.0  3.5 Silica                                                                            0.25                                                                              Silica                                                                           1.46 a   58.7                                                                              24.6                                                                              PC                                 1-2(Comp.)                                                                          3.0  3.5 PMMA                                                                              0.25                                                                              Silica                                                                           1.46 a   42.6                                                                              19.4                                                                              PC                                 1-3(Comp.)                                                                          3.0  3.5 Silica                                                                            0.03                                                                              TiO.sub.2                                                                        2.76 a   59.1                                                                              23.1                                                                              PC                                 1-4(Comp.)                                                                          3.0  0.2 Silica                                                                            0.01                                                                              Silica                                                                           1.46 a   138.9                                                                             84.5                                                                              PC                                 1-5(Comp.)                                                                          3.0  3.5 Silica                                                                            --  -- --   --  63.5                                                                              26.4                                                                              PC                                 __________________________________________________________________________     *a: Hydrophilic b: Hydrophobic                                           

As can be seen from Table 1, inventive samples 1-1 to 1-4 in which fineparticles having a refractive index of 1.40 to 1.60 are incorporated,were markedly superior in transmission visibility, as compared tocomparative sample 1-5 in which fine particles were not incorporated andsample 1-3 in which fine titanium oxide particles having a refractiveindex of more than 1.60. Further, from comparison of inventive samples1-1 to 1-4, fine silica particles were shown to be preferable than finepolymethyl methacrylate (PMMA) particles, with respect to transmissionvisibility. Regarding the average particle size of the fine particles,inventive sample 1-1 of 0.01 μm or less was shown to be markedlysuperior in transmission visibility to comparative sample 1-1 of 0.25μm. From comparison of inventive samples 1-1, 1-7 and comparative sample1-4 with respect to glossiness and transmission visibility, the averageparticle size is shown to be preferable with a range of 0.25 to 10 μm.Furthermore, from comparison of inventive samples 1-1 and 1-5 withrespect to transmission visibility, silica particles were shown to bemore preferable than PMMA particles.

Example 2

Preparation of Inventive Sample 2-1

Using the polycarbonate film with a thickness of 80 mm used in sample1-1 of example 1, UV ray-hardenable resin composition D was coated onthe b-side of the film so as to have a dry thickness of 0.3 μm and driedat 80° C. for 5 min. Subsequently, the coat was exposed to UV lightemitted from a high pressure UV lamp at a distance of 10 cm apart for 4sec. to form UV-hardened resin layer A. Next, on the a-side, the lowerlayer solution (1) and upper layer solution (2) of theadhesion-facilitating layer (a) were each coated in this order in acoating amount of 20 ml/m² and dried at 100° C. for 5 min. to obtain aninventive sample 2-1.

Preparation of Inventive Sample 2-2

Using the polycarbonate film with a thickness of 80 mm used in sample1-1 of example 1, UV ray-hardenable resin composition E was coated onthe b-side of the film so as to have a dry thickness of 0.5 μm and driedat 80° C. for 5 min. Subsequently, the coat was exposed to UV lightemitted from a high pressure UV lamp at a distance of 10 cm apart for 4sec. to form UV-hardened resin layer A. Next, on the a-side, the lowerlayer solution (1) and upper layer solution (2) of theadhesion-facilitating layer (a) were each coated in this order in acoating amount of 20 ml/m² and dried at 100° C. for 5 min. to obtain aninventive sample 2-2.

Preparation of Inventive Sample 2-3

Using the polycarbonate film with a thickness of 80 mm used in sample1-1 of example 1, UV ray-hardenable resin composition F was coated onthe b-side of the film so as to have a dry thickness of 2.5 μm and driedat 80° C. for 5 min. Subsequently, the coat was exposed to UV lightemitted from a high pressure UV lamp at a distance of 10 cm apart for 4sec. to form UV-hardened resin layer A. Next, on the a-side, the lowerlayer solution (1) and upper layer solution (2) of theadhesion-facilitating layer (a) were each coated in this order in acoating amount of 20 ml/m² and dried at 100° C. for 5 min. to obtain aninventive sample 2-3.

Preparation of Inventive Sample 2-4

Inventive sample 2-4 was prepared in the same manner as inventive sample2-3, except that 2 parts by weight of silica (average particle size of1.0 μm) of UV ray-hardenable resin F was replaced by 2 parts by weightof silica (average particle size of 1.38 μm).

Preparation of Inventive Sample 2-5

Inventive sample 2-5 was prepared in the same manner as inventive sample2-3, except that 2 parts by weight of silica (average particle size of1.0 μm) of UV ray-hardenable resin F was replaced by 2 parts by weightof silica (average particle size of 1.88 μm) and 2 parts by weight ofhydrophilic silica (average particle size of 0.01 μm) was replaced by 2parts by weight of hydrophilic silica (average particle size of 0.005μm).

Preparation of Inventive Sample 2-6

Inventive sample 2-6 was prepared in the same manner as inventive sample2-3, except that 2 parts by weight of silica (average particle size of1.0 μm) of UV ray-hardenable resin F was replaced by 2 parts by weightof silica (average particle size of 1.88 μm) and 2 parts by weight ofhydrophilic silica (average particle size of 0.01 μm) was replaced by 1parts by weight of hydrophilic silica (average particle size of 0.005μm).

Preparation of Inventive Sample 2-7

Inventive sample 2-7 was prepared in the same manner as inventive sample2-3, except that 2 parts by weight of silica (average particle size of1.0 μm) of UV ray-hardenable resin F was replaced by 2 parts by weightof silica (average particle size of 1.88 μm).

Preparation of Inventive Sample 2-8

Inventive sample 2-8 was prepared in the same manner as inventive sample2-3, except that 2 parts by weight of silica (average particle size of1.0 μm) of UV ray-hardenable resin F was replaced by 2 parts by weightof silica (average particle size of 1.88 μm) and 2 parts by weight ofhydrophilic silica (average particle size of 0.01 μm) was replaced by 1part by weight of hydrophobic silica (average particle size of 0.01 μm).

Preparation of Inventive Sample 2-9

Inventive sample 2-9 was prepared in the same manner as inventive sample2-3, except that 2 parts by weight of silica (average particle size of1.0 μm) of UV ray-hardenable resin F was replaced by 1 parts by weightof silica (average particle size of 1.88 μm).

Preparation of Inventive Sample 2-10

Inventive sample 2-10 was prepared in the same manner as inventivesample 2-3, except that 2 parts by weight of silica (average particlesize of 1.0 μm) of UV ray-hardenable resin F was replaced by 4 parts byweight of silica (average particle size of 1.88 μm).

Preparation of Inventive Sample 2-11

Inventive sample 2-11 was prepared in the same manner as inventivesample 2-3, except that 2 parts by weight of silica (average particlesize of 1.0 μm) of UV ray-hardenable resin F was replaced by 2 parts byweight of silica (average particle size of 1.88 μm) and 2 parts byweight of hydrophilic silica (average particle size of 0.01 μm) wasreplaced by 2 parts by weight of hydrophilic silica (average particlesize of 0.08 μm).

Preparation of Inventive Sample 2-12

Inventive sample 2-10 was prepared in the same manner as inventivesample 2-3, except that 2 parts by weight of silica (average particlesize of 1.0 μm) of UV ray-hardenable resin F was replaced by 2 parts byweight of silica (average particle size of 2.5 μm).

Preparation of Inventive Sample 2-13

Inventive sample 2-13 was prepared in the same manner as inventivesample 2-3, except that 2 parts by weight of silica (average particlesize of 1.0 μm) of UV ray-hardenable resin F was replaced by 2 parts byweight of silica (average particle size of 3.75 μm).

Preparation of Inventive Sample 2-14

Using the polycarbonate film with a thickness of 80 mm used in sample1-1 of example 1, UV ray-hardenable resin composition G was coated onthe b-side of the film so as to have a dry thickness of 5.0 μm and driedat 80° C. for 5 min. Subsequently, the coat was exposed to UV lightemitted from a high pressure UV lamp at a distance of 10 cm apart for 4sec. to form UV-hardened resin layer A. Next, on the a-side, the lowerlayer solution (1) and upper layer solution (2) of theadhesion-facilitating layer (a) were each coated in this order in acoating amount of 20 ml/m² and dried at 100° C. for 5 min. to obtain aninventive sample 2-14.

Preparation of Inventive Sample 2-15

Using the polycarbonate film with a thickness of 80 mm used in sample1-1 of example 1, UV ray-hardenable resin composition H was coated onthe b-side of the film so as to have a dry thickness of 6.0 μm and driedat 80° C. for 5 min. Subsequently, the coat was exposed to UV lightemitted from a high pressure UV lamp at a distance of 10 cm apart for 4sec. to form UV-hardened resin layer A. Next, on the a-side, the lowerlayer solution (1) and upper layer solution (2) of theadhesion-facilitating layer (a) were each coated in this order in acoating amount of 20 ml/m² and dried at 100° C. for 5 min. to obtain aninventive sample 2-15.

Preparation of Inventive Sample 16

Inventive sample 2-16 was prepared in the same manner as inventivesample 2-7, except that cellulose triacetate film with a thickness of 80μm used in sample 1-6 of example 1 was used and on the a-side thereof, acoating solution of the adhesion-facilitating layer (b) was coated.

Preparation of Comparative Sample 2-1

Comparative sample 2-1 was prepared in the same manner as inventivesample 2-3, except that 2 parts by weight of silica (average particlesize of 1.0 μm) of UV ray-hardenable resin F was replaced by 2 parts byweight of silica (average particle size of 1.88 μm) and 2 parts byweight of hydrophilic silica (average particle size of 0.01 μm) wasreplaced by 2 parts by weight of hydrophilic silica (average particlesize of 0.25 μm).

Preparation of Comparative Sample 2-2

Inventive sample 2-2 was prepared in the same manner as inventive sample2-3, except that 2 parts by weight of silica (average particle size of1.0 μm) of UV ray-hardenable resin F was replaced by 2 parts by weightof silica (average particle size of 1.88 μm) and without using 2 partsby weight of hydrophilic silica (average particle size of 0.01 μm),composition I was prepared.

The refractive index of hydrophilic silica fine particles contained inUV ray-hardenable resins of thus-prepared inventive samples 2-1 through2-16 and comparative samples 2-1 and 2-2 was proved to be 1.45. Thesesamples were each evaluated according to the following manner.

Evaluation of Glare-proof

Samples were evaluated in the same manner as in Example 1. Resultsthereof are shown in Table 2.

Evaluation of Hardness

Pencil hardness was measured with respect to the UV ray-hardenable resinlayer-side of each sample. Measurements were made at a load of 100 g, inaccordance with JIS K5401.

Evaluation of Transmission Visibility

Samples were evaluated in the same manner as in Example 1. Resultsthereof are shown in Table 2.

Evaluation of Sparkle

Using inventive samples 2-1 through 2-16 and comparative samples 2-1 and2-2 as a protective film of a polarizing plate, polarizing plates wereprepared according to the following manner.

(i) Initially, a polarizing membrane was prepared. A polyvinyl alcoholfilm with a thickness of 120 μm was dipped in an aqueous solutioncomprised of iodine of 1 part, potassium iodide of 2 parts and boricacid of 4 parts and then stretched by a factor of four at 50° C. toobtain the polarizing membrane.

(ii) A protective film which is cut in a size of 30 cm in a longitudinaldirection and 18 cm in width direction, is arranged on a glass plate sothat its a-side is upside down.

(iii) The above polarizing membrane at an identical size as theprotective film is dipped for 1 to 2 sec in an adhesive-bath containing2 wt. % polyvinyl alcohol.

(iv) Excess adhesive adhered to the polarizing membrane is carfullywiped off. The polarizing membrane is then placed on the protective filmarranged as in (ii) so that the adhesive is brought into contact withthe a-side of the protective film.

(v) The polarizing membrane is laminated to the protective film, withmanual pressure using a hand-roller to remove any excess adhesive and/orair bubbles. Pressure on the hand-roller is about 2 to 3 kg/cm² at aroller speed of about 2 m/min.

(vi) The resulting sample is allowed to stand for 2 min. in a dryingchamber at 80° C.

Each of thus-prepared polarizing plate was built in the surface side of9.5 inch TFT full color liquid crystal display (picture element no. of307200, i.e., 640×480 dots; picture element pitch of 0.30×0.30 mm). Theindicator of the liquid crystal display was set to "overall white",then, sparkle (abnormal luminance) was visually observed and evaluatedbased on the following criteria.

A: Not observed level

B: Slightly observed level

C: Observed level

Results thereof are shown in Table 2.

                                      TABLE 2                                     __________________________________________________________________________                                                 Trans-                           Layer      Coarse particles                                                                       Fine particles           mission                                thickness                                                                          Av.size                                                                           Amount                                                                             Av.size Amount                                                                             Glossi-                                                                           Hard-                                                                             Spar-                                                                             visi-                            Sample No.                                                                          (μm)                                                                            (μm)                                                                           (wt.parts)                                                                         (μm)                                                                           surface                                                                           (wt.parts)                                                                         ness                                                                              ness                                                                              kle bility                           __________________________________________________________________________    2-1(Inv.)                                                                           0.3  0.45                                                                              2    0.01                                                                              a   2    50.3                                                                              3H  A   125.1                            2-2(Inv.)                                                                           0.5  0.75                                                                              2    0.01                                                                              a   2    51.7                                                                              5H  A   121.7                            2-3(Inv.)                                                                           2.5  2.0 2    0.01                                                                              a   2    89.1                                                                              >6H**                                                                             A   110.3                            2-4(Inv.)                                                                           2.5  2.75                                                                              2    0.01                                                                              a   2    67.8                                                                              >6H A   98.0                             2-5(Inv.)                                                                           2.5  3.75                                                                              2    0.005                                                                             a   2    49.0                                                                              >6H A   127.1                            2-6(Inv.)                                                                           2.5  3.75                                                                              2    0.01                                                                              a   1    49.3                                                                              >6H A   110.2                            2-7(Inv.)                                                                           2.5  3.75                                                                              2    0.01                                                                              a   2    48.2                                                                              >6H A   128.4                            2-8(Inv.)                                                                           2.5  3.75                                                                              2    0.01                                                                              a   2    49.4                                                                              >6H A   82.5                             2-9(Inv.)                                                                           2.5  3.75                                                                              1    0.01                                                                              b   2    68.6                                                                              >6H A   138.2                            2-10(Inv.)                                                                          2.5  3.75                                                                              4    0.01                                                                              a   2    33.0                                                                              >6H A   96.4                             2-11(Inv.)                                                                          2.5  3.75                                                                              2    0.08                                                                              a   2    47.1                                                                              >6H A   110.3                            2-12(Inv.)                                                                          2.5  5.0 2    0.01                                                                              a   2    38.8                                                                              >6H A   92.1                             2-13(Inv.)                                                                          2.5  7.5 2    0.01                                                                              a   2    32.5                                                                              >6H B   78.0                             2-14(Inv.)                                                                          5.0  7.5 2    0.01                                                                              a   2    49.9                                                                              >6H A   92.5                             2-15(Inv.)                                                                          6.0  9.0 2    0.01                                                                              a   2    50.0                                                                              >6H B   85.2                             2-16(Inv.)                                                                          2.5  3.75                                                                              2    0.01                                                                              a   2    48.4                                                                              >6H A   127.5                            2-1(Comp.)                                                                          2.5  3.75                                                                              2    0.25                                                                              a   2    45.3                                                                              >6H B   29.7                             2-2(Comp.)                                                                          2.5  3.75                                                                              2    --  --  --   50.3                                                                              >6H B   30.8                             __________________________________________________________________________     *a: Hydrophilic b: Hydrophobic                                                **more than 6H                                                           

As can be seen from Table 2, it was shown as follows. From comparison ofinventive samples 2-7 and 2-8, hydrophilic fine particles was shown tobe superior in transmission visibility to hydrophobic ones. As to theaverage particle size of fine particles, that of 0.1 μm or less wasmarkedly superior in transmission visibility (inventive sample 2-11 vs.comparative sample 2-1). Further, the average fine particle size of0.015 μm or less is more preferred (inventive samples 2-7 and 11).Furthermore, addition of the fine particles led to marked improvementsin transmission visibility, as shown from comparison of inventivesamples 2-7 and 11 with comparative sample 2.

As to the thickness of the glare-proof layer 10, the range of 0.5 to 5.0μm is preferred and 2.0 to 4.0 μm is more preferred, as shown fromresults of regarding pencil hardness and sparkle of inventive samples2-1, 2, 7, 14 and 15. The average size of the particles (i.e., the firstparticles, as claimed) was preferably 1.1 to 2.0 and more preferably notless than 1.5 times the layer thickness., as shown from resultsregarding glossiness and sparkle of inventive samples 2-3, 4, 7, 12 and13. The addition amount of the particles was preferably 2 parts byweight or less of the binder, as shown from results regarding glossinessof inventive samples 2-7, 9 and 10.

What is claimed is:
 1. A protective film for use with a polarizing plate comprising a support having on one side thereof a glare-proof layer, wherein said glare-proof layer comprises coarse particles having an average particle size of 0.25 to 10 μm and fine particles having an average particle size no greater than 0.1 μm and a refractive index of 1.40 to 1.60, and wherein said fine particles are hydrophilic particles having a moisture content no less than 0.5% by weight.
 2. The protective film of claim 1, wherein said coarse particles and said fine particles independently are comprised of one selected from the group consisting of silicon oxide, titanium oxide, aluminium oxide, zinc oxide, tin oxide, calcium carbonate, barium sulfate, talc, kaolin, and calcium sulfate.
 3. The protective film of claim 2, wherein said coarse particles and fine particles are comprised of silicon oxide.
 4. The protective film of claim 1, wherein said coarse particles and said fine particles independently are comprised of one selected from the group consisting of a polyacrylate, polymethacrylate, silicone resin, polystyrene, polycarbonate, polyacryl-styrene, benzoguanamine type resin, melamine type resin, polyolefin resin, polyester resin, polyamide, polyimide, and polyfluoroethylene.
 5. The protective film of claim 1, wherein said glare-proof layer is a hardened layer being obtained by hardening a layer containing a resin capable of being hardened upon exposure to actinic ray.
 6. The protective film of claim 5, wherein said resin is selected from the group consisting of an ultraviolet ray hardenable resin and an electron beam hardenable resin.
 7. The protective film of claim 1, wherein a adhesion-facilitating layer is provided on the other side of the support opposite to the glare-proof layer.
 8. A polarizing plate comprising a polarizing film containing a polarizer and provided thereon a protective film which comprises a support having thereon a glare-proof layer, wherein said glare-proof layer comprises coarse particles having an average particle size of 0.25 to 10 μm, and fine particles having an average particle size no greater than 0.1 μm and a refractive index of 1.40 to 1.60, and wherein said fine particles are hydrophilic particles having a moisture content no less than 0.5% by weight.
 9. The polarizing plate of claim 8, wherein said coarse particles and said fine particles independently are comprised of one selected from the group consisting of silicon oxide, titanium oxide, aluminium oxide, zinc oxide, tin oxide, calcium carbonate, barium sulfate, talc, kaolin, and calcium sulfate.
 10. The polarizing plate of claim 9, wherein said coarse particles and fine particles are comprised of silicon oxide.
 11. The polarizing plate of claim 8, wherein said coarse particles and said fine particles independently are comprised of one selected from the group consisting of a polyacrylate, polymethacrylate, silicone resin, polystyrene, polycarbonate, polyacryl-styrene, benzoguanamine type resin, melamine type resin, polyolefin resin, polyester resin, polyamide, polyimide, and polyfluoroethylene.
 12. The polarizing plate of claim 8, wherein said glare-proof layer is a hardened layer being obtained by hardening a layer containing a resin capable of being hardened upon exposure to actinic ray.
 13. The polarizing plate of claim 12, wherein said resin is selected from the group consisting of an ultraviolet ray hardenable resin and an electron beam hardenable resin.
 14. A protective film for use with a polarizing plate comprising a support having on one side thereof a glare-proof layer, wherein said glare-proof layer comprises coarse particles having an average particle size of 0.25 to 10 μm and fine particles having an average particle size which is 0.005 to 0.1 μm and a refractive index of 1.40 to 1.60, and wherein said glare-proof layer has a thickness of 0.5 to 5.0 μm and the average particle size of said coarse particles is 1.1 to 2 times the thickness of said glare-proof layer.
 15. The protective film of claim 14, wherein said coarse particles and fine particles are comprised of silicon oxide.
 16. A polarizing plate comprising a polarizing film containing a polarizer and provided thereon a protective film which comprises a support having thereon a glare-proof layer, wherein said glare-proof layer comprises coarse particles having an average particle size of 0.25 to 10 μm and fine particles having an average particle size which is 0.005 to 0.1 μm and a refractive index of 1.40 to 1.60, and wherein said glare-proof layer has a thickness of 0.5 to 5.0 μm and the average particle size of said coarse particles is 1.1 to 2 times the thickness of said glare-proof layer.
 17. The polarizing plate of claim 16, wherein said coarse particles and fine particles are comprised of silicon oxide. 